There is a desire to reduce weight in many manufactured articles. The need is acute in the manufacture of automotive vehicles but is not limited to such applications. The ability to integrate multiple thicknesses into a single part is useful for minimizing overall part mass without sacrificing strength or stiffness in selected regions. Also thin gage parts, such as sheet metal, frequently afford limited thread engagement, and thus limited holding power, for threaded fasteners. Thus the ability to selectively introduce thicker regions into a part enables the use of threaded fasteners without compromising retention, thereby facilitating part removal for replacement or service.
Aluminum alloys and magnesium alloys are available for automotive body applications and the like but these light weight materials are not usually as formable as many ferrous alloys. Metal sheets of suitable alloys of aluminum and magnesium have been formed into body panels and the like by stamping, warm stamping, fluid forming and hot blow forming. But the starting materials for such forming processes are usually sheets of uniform thickness which limit the shapes of articles that can be formed. Often it is desired to make other more complicated shapes of the same alloys such as reinforcement parts, attachment parts, stiffening parts and the like that have sections of varying thickness.
There remains a need for forming practices that can complement stamping, warm stamping or hot blow forming or the like and be applied to a primary shape light metal alloy workpiece like, for example, a billet, bar, strip, or sheet, and form the workpiece into an article having sections of varying thicknesses and, often, at varying and sharp angles.